Vibration Analysis and Human Comfort Assessment of Pedestrian Footbridges when Subjected to Dynamic Vandalism Loads

Resumo

This research work aims to investigate the dynamic structural behaviour of pedestrian footbridges, when subjected to dynamic actions associated with vandalism (rhythmic human loads), based on the development of experimental tests and numerical modelling. The investigated pedestrian footbridge is associated to a simply supported concrete structure with span of 24.4 m, currently used for pedestrian crossing and located at the Faculty of Engineering (FEN) of the Rio de Janeiro State University (UERJ). Initially, an experimental modal analysis was performed on the investigated footbridge, in order to identify and assess the global dynamic behaviour of the system. After that, several loading scenarios were idealized to carry out experimental forced vibration tests on the structure, with the participation of up to 20 people, aiming to simulate dynamic excitations associated with vandalism loads. Subsequently, a finite element model was developed and calibrated based on experimental results, considering traditional mathematical functions, corresponding to only-force models, in order to represent human-induced dynamic loads related to vandalism. Based on the forced vibration experimental tests and the dynamic analysis, the footbridge dynamic structural response was investigated. The results of this study indicated that excessive vibrations and human discomfort can occur from fifteen people jumping on the analysed pedestrian footbridge.